Analysis of lightning events preceding upward flashes from Gaisberg and Säntis Towers

In this paper, we present an analysis of the initiation of upward lightning flashes for the Gaisberg and the Säntis Towers. The results are compared with previous studies. It is found that the majority of upward lightning discharges from both towers are initiated without any preceding lightning activity. We show also that the results of the presented studies on the initiation of upward flashes from tall structures might be affected by the selected parameters of the study.